This invention relates to large earth excavators, and more particularly to a method of fabricating the base of an excavator at the site at which the excavator is to be used.
Certain excavators have large circular bases that support a rotating mechanism for an upper works and the drive mechanisms for rotating the upper works. Such bases have been built in diameters up to 105 feet. Such bases can have internal diaphragms located in a circumferential, radial, rectangular, or triangular pattern, or combinations thereof. Excavator bases have been constructed in factories. Because of their size, the bases must be built in segments or sections. Sometimes these segments or sections are assembled in the factory to check for fit, disassembled, and then the segments or sections are shipped piece by piece to the job site at which the base will be assembled. The base segments or sections are then reassembled and welded together, machined as required, and then assembled to the excavator.
FIGS. 1, 2, and 3 of the drawings illustrate one example of an excavator base designed for fabrication in a factory. This excavator base is characterized by being formed from a series of outer segments A (FIG. 1), inner segments B (FIGS. 1 and 3), central segments C (FIG. 1), and a base center D (FIG. 1). Each of the elements A, B, C and D are separately built and assembled together in the factory. The elements are subsequently disassembled and placed on flat bed trailers or railroad cars for transportation to the site. The size of such trailers or railroad cars dictate the maximum size of the individual elements. The maximum size of the individual elements also dictates the design of the interior diaphragms. When segments are used as in FIGS. 1-3, radial diaphragms and tangential diaphragms of many sizes and shapes are dictated.
This invention provides a method for the on-site fabrication of an excavator base allowing for optimization of design without concern for shipping constraints of large sections.